fix(FN-2444): polish node dashboard UX and discovery core handling

- Update node management UI components to use shared form/button classes, semantic color tokens, and accessible interactions
- Refine mesh topology rendering and related dashboard tests for improved readability and behavior coverage
- Adjust discovery routes to reuse injected centralCore instances without unnecessary init/close cycles
- Add/extend tests for shared CentralCore discovery flows and model settings scope save behavior

packages/engine/src/pi-create-fn-agent.test.ts

@@ -154,7 +154,7 @@ describe("worktree path boundary helpers", () => {
         error: expect.stringContaining("outside the worktree boundary"),
       });
       expect(mockReadTool.execute).not.toHaveBeenCalled();
-    });
+    }, 15_000);
 
     it("allows project root .fusion/memory/ files from worktree session", async () => {
       const mockReadTool = {